WPF:将标签绑定到类属性

问题描述：

我试图将标签的内容绑定到类实例的字符串属性，但没有取得多大成功.

I'm trying to get the content of a label to bind to the string property of a class instance without much success.

XAML:

<Window x:Class="WPFBindingTest.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300">    
<Grid>        
    <Label Height="28" Margin="12,55,106,0" Name="label1" Background="Bisque"
           Content="{Binding Source=MyFoo, Path=W1}" VerticalAlignment="Top" />

    <Label Height="28" Margin="12,12,106,0" Name="label2" Background="Bisque"
           Content="{Binding Source=MyFoo, Path=W2}"  VerticalAlignment="Top" />

    <Button Height="23" HorizontalAlignment="Right" Margin="0,0,32,48"
            Name="button1" VerticalAlignment="Bottom" Width="89"
            Click="button1_Click">
        Set Properties
    </Button>

</Grid>   
</Window>

C#:

namespace WPFBindingTest
{
   public partial class Window1 : Window
    {
        public Foo MyFoo;

        public Window1()
        {
            InitializeComponent();            

            MyFoo = new Foo();           
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {      
            MyFoo.W1 = "Hello";
            MyFoo.W2 = "Dave";
        }
    }

    public class Foo
    {
        public string W1 { get; set; }
        public string W2 { get; set; }
    }
}

即当我单击按钮时，我将 MyFoo 的属性设置为Hello"和Dave"，并希望将其反映在 UI 上的标签中.我已将内容设置为绑定，但有些不对劲.我在这里做错了什么?

i.e. when I click the button, I set the properties of MyFoo to "Hello" and "Dave", and want that reflected in the labels on the UI. I've set the Content as a binding but something isn't right. What am I doing wrong here?

答

您可以将 MyFoo 设为依赖属性，并将 DataContext 设置为您的 Window1 实例:

You may make your MyFoo a dependency property and set the DataContext to your Window1 instance:

<Window DataContext="{Binding RelativeSource={RelativeSource Self}}" ...>

查看这篇文章更多详情.

使 MyFoo 成为依赖属性不是强制性的.如果您在分配 DataContext 之前设置属性值，它可能只适用于一个属性.(但永远不要使用字段.)但是，如果您希望标签获取 W1 和 W2 的变化值(或者您不知道/关心这些值在分配 DataContect 之前或之后设置)，你需要 Foo 要么是一个 DependencyObject，要么实现接口 INotifyPropertyChanged.

Making MyFoo a dependency property is not compulsory. it may work with just a property if you set the property value before assigning the DataContext. (But never with a field.) However if you want the labels to pick up the changing values of W1 and W2 (or you don't know/care if the values are set before or after assigning the DataContect), you need Foo to be either a DependencyObject, or implement interface INotifyPropertyChanged.

WPF:将标签绑定到类属性

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